If Statement

If statement
($this->post('onething') == 'something' ? 'Then this' : 'Or this')

Read an array

implode()

Display PDF

    $file = 'myfile.pdf';
$file1 = '/file-dir/'.$file;

ob_clean();
header("Cache-Control: no-store");
header("Expires: 0");
header("Content-Type: application/pdf");
header("Cache-Control: public");
header('Content-Disposition: inline; filename="' . $file . '"');
header("Content-Transfer-Encoding: binary");
header('Accept-Ranges: bytes');
readfile($file1);